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Mirrors > Home > MPE Home > Th. List > fac3 | Structured version Visualization version GIF version |
Description: The factorial of 3. (Contributed by NM, 17-Mar-2005.) |
Ref | Expression |
---|---|
fac3 | ⊢ (!‘3) = 6 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-3 12328 | . . 3 ⊢ 3 = (2 + 1) | |
2 | 1 | fveq2i 6910 | . 2 ⊢ (!‘3) = (!‘(2 + 1)) |
3 | 2nn0 12541 | . . 3 ⊢ 2 ∈ ℕ0 | |
4 | facp1 14314 | . . 3 ⊢ (2 ∈ ℕ0 → (!‘(2 + 1)) = ((!‘2) · (2 + 1))) | |
5 | 3, 4 | ax-mp 5 | . 2 ⊢ (!‘(2 + 1)) = ((!‘2) · (2 + 1)) |
6 | fac2 14315 | . . . 4 ⊢ (!‘2) = 2 | |
7 | 2p1e3 12406 | . . . 4 ⊢ (2 + 1) = 3 | |
8 | 6, 7 | oveq12i 7443 | . . 3 ⊢ ((!‘2) · (2 + 1)) = (2 · 3) |
9 | 2cn 12339 | . . . 4 ⊢ 2 ∈ ℂ | |
10 | 3cn 12345 | . . . 4 ⊢ 3 ∈ ℂ | |
11 | 9, 10 | mulcomi 11267 | . . 3 ⊢ (2 · 3) = (3 · 2) |
12 | 3t2e6 12430 | . . 3 ⊢ (3 · 2) = 6 | |
13 | 8, 11, 12 | 3eqtri 2767 | . 2 ⊢ ((!‘2) · (2 + 1)) = 6 |
14 | 2, 5, 13 | 3eqtri 2767 | 1 ⊢ (!‘3) = 6 |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1537 ∈ wcel 2106 ‘cfv 6563 (class class class)co 7431 1c1 11154 + caddc 11156 · cmul 11158 2c2 12319 3c3 12320 6c6 12323 ℕ0cn0 12524 !cfa 14309 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-10 2139 ax-11 2155 ax-12 2175 ax-ext 2706 ax-sep 5302 ax-nul 5312 ax-pow 5371 ax-pr 5438 ax-un 7754 ax-cnex 11209 ax-resscn 11210 ax-1cn 11211 ax-icn 11212 ax-addcl 11213 ax-addrcl 11214 ax-mulcl 11215 ax-mulrcl 11216 ax-mulcom 11217 ax-addass 11218 ax-mulass 11219 ax-distr 11220 ax-i2m1 11221 ax-1ne0 11222 ax-1rid 11223 ax-rnegex 11224 ax-rrecex 11225 ax-cnre 11226 ax-pre-lttri 11227 ax-pre-lttrn 11228 ax-pre-ltadd 11229 ax-pre-mulgt0 11230 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-nf 1781 df-sb 2063 df-mo 2538 df-eu 2567 df-clab 2713 df-cleq 2727 df-clel 2814 df-nfc 2890 df-ne 2939 df-nel 3045 df-ral 3060 df-rex 3069 df-reu 3379 df-rab 3434 df-v 3480 df-sbc 3792 df-csb 3909 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-pss 3983 df-nul 4340 df-if 4532 df-pw 4607 df-sn 4632 df-pr 4634 df-op 4638 df-uni 4913 df-iun 4998 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5583 df-eprel 5589 df-po 5597 df-so 5598 df-fr 5641 df-we 5643 df-xp 5695 df-rel 5696 df-cnv 5697 df-co 5698 df-dm 5699 df-rn 5700 df-res 5701 df-ima 5702 df-pred 6323 df-ord 6389 df-on 6390 df-lim 6391 df-suc 6392 df-iota 6516 df-fun 6565 df-fn 6566 df-f 6567 df-f1 6568 df-fo 6569 df-f1o 6570 df-fv 6571 df-riota 7388 df-ov 7434 df-oprab 7435 df-mpo 7436 df-om 7888 df-2nd 8014 df-frecs 8305 df-wrecs 8336 df-recs 8410 df-rdg 8449 df-er 8744 df-en 8985 df-dom 8986 df-sdom 8987 df-pnf 11295 df-mnf 11296 df-xr 11297 df-ltxr 11298 df-le 11299 df-sub 11492 df-neg 11493 df-nn 12265 df-2 12327 df-3 12328 df-4 12329 df-5 12330 df-6 12331 df-n0 12525 df-z 12612 df-uz 12877 df-seq 14040 df-fac 14310 |
This theorem is referenced by: fac4 14317 4bc2eq6 14365 ef4p 16146 ef01bndlem 16217 |
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